The factors that need to be taken into account when
quantifying a given impact of transport emissions of air
pollution are therefore as follows:
f emissions during complete life cycle of vehicle, fuel and
associated infrastructure;
f signi"cance of transport emissions compared with
other sources of the same pollutant(s) within a given
geographical area, as shown by emissions inventory
data;
f contribution of sources outside the geographical area
covered by the emissions inventory;
f source}receptor relationships;
f other pollutants contributing to or exacerbating the
impact of interest;
f other impacts of the pollutant(s) of interest.